The present invention relates to a device for the wireless transmission of a tripping (triggering) signal for a restraint system.
In German Published Patent Application No. 198 29 730 is discussed a device which couples electrical elements in the steering wheel and in the steering wheel column of a motor vehicle via a magnetic transformer. Processors designed for data transmission over the transformer are positioned both on the primary as well as on the secondary side of the transformer. Furthermore, elements are provided which make possible a transmission of energy (power) via the transformer.
In German Published Patent Application No. 197 53 467 is discussed a circuit for data and energy transmission in a motor vehicle. Firing commands are wirelessly transmitted via a transformer from a firing bus to firing means, a modulator being used for this purpose. On the secondary side, the transmitted signals are evaluated, and, in the event of a firing command, the control circuit then drives firing circuits. European Published Patent Application No. 0 679 554 discusses that a tripping signal is transmittable from a steering column to the steering wheel. Here, too, a signal evaluation is performed on the steering-wheel side, the secondary side, that is. The signal evaluation then drives restraining means, if appropriate.
The exemplary device according to the present invention for the wireless transmission of a tripping signal for a restraint system is believed to have the advantage that no additional delays should occur in the transmission of tripping commands as a result of conversions, interpretations, or any other electronic processing, so that the tripping signal may be transmitted to the restraint system via the transformer without buffer storage. In this way, the safety of vehicle occupants may be increased because, the restraint system can react more rapidly to tripping commands.
It is believed to be advantageous that the tripping device includes a bus simulation so as to be able to use the same tripping commands for the firing and tripping circuits to be driven, as are used for the restraining systems that are directly connected to the bus, in this case, the firing bus. In this manner, all restraining systems used in a vehicle may be equipped with the same tripping devices in accordance with their function. This results in a simplification of the installation and the conception of the tripping devices.
It is also believed to be advantageous that a transmission path that heretofore has not been suitable for firing bus signals, namely the transformer, is now nevertheless used for transmitting firing signals, i.e., tripping signals. In this context, a simple electrical filtering is used to form a tripping signal from the tripping command, a direct component being removed. The firing or tripping signal can then be transmitted via the transformer. Other possibilities for detecting the tripping command on the firing bus are to compare the amplitude swing of the firing signal to a reference amplitude and to use the push-pull operation, standard in a tripping command, in comparison with other signals transmitted on the bus. For this purpose, it may be advantageous to use comparators and edge-triggered gates.
It is believed to be particularly advantageous to use a filter having a simple high pass and, if appropriate, also an amplifier or driver, so that a rapid conversion of the tripping command into the tripping signal may be assured using the filter. This should ensure a very xe2x80x9csimplexe2x80x9d design of the filter.
Furthermore, it is believed to be advantageous that, in addition to the tripping signals, diagnostic and/or control signals may also be transmitted via the transformer.
It is also believed to be advantageous, that on the primary side, a modulator is provided and on the secondary side a demodulator, to modulate the tripping signals to be transmitted via the transformer such that an improved transmission via the transformer is made possible. This is achieved, for example, by a frequency conversion. The demodulator determines the tripping signal from the signals that have been modulated via the transformer.
It is also believed to be advantageous if the tripping device has at least one firing circuit for at least one airbag and/or tripping circuit for belt tighteners, the tripping device being arranged either in a vehicle seat or in a steering wheel.
Furthermore, it is believed to be advantageous if the transformer is configured so as to be either inductive or capacitative, so that in accordance with the installation, the more appropriate transmission principle can be applied.
It is also believed to be advantageous if the tripping device has a bus simulation, so as to use the same tripping commands for the firing circuits to be driven and the tripping circuits as for the restraint systems, which are directly connected to the bus, here to the firing bus. In this manner, all of the restraint systems used in the vehicle are equipped with the same tripping devices in accordance with their function. This should result in a simplification of the installation and conception of the tripping devices.
Finally, it is also believed to be advantageous that a common housing is provided for the electrical elements on the primary side of the transformer, the control unit for the restraint system also being integrated in the housing, so that a separate housing may not be required.